Re: [Qemu-devel] [v2 1/2] docs: Add a doc about multiple compression threads

[Li, Liang Z]

>OK, some high level questions:
>
> 1) How does the performance compare to running a separate compressor process 
> in the stream rather than embedding it in the qemu?
>

I have not do the test, so I don't know the performance. Maybe I can do it 
later.

>  2) Since you're looking at different compression schemes do we need 
> something in the settings to select it, and to say what makes sense
>for the 'compress_level'?   For example I don't know if lz4 or quicklz
>have 1-10 for their compression levels?  How do I know which compression 
>schemes are available on any host?
>

Only the LZ4HC support compression level, which range from 0 to 16. My 
implementation does not support selecting different compression schemes, it 
only support selecting different compression level. Using LZ4HC can actually 
help to improve the performance compared to using zlib, on the other hand, it's 
not widespread as zlib, and the License is another problem.

Liang